LIST OF TABLES

LIST OF FIGURES

1.0 Introduction

Viacom's implementing a Long-term Groundwater Monitoring Plan for Bennett's Dump (Reference 11), per the requirements of the SOW (Reference 7). In addition, Viacom is voluntarily undertaking this investigation work to increase understanding of the Bennett's Dump site hydrogeology.

This document describes the plan for that investigation.

Stout's Creek is the main surface water body associated with the site, flowing from south to north along the western edge of the site. All known springs and surface storm water eventually flow into Stout's Creek. Open quarry pits in the area collect surface water and groundwater. The water from the quarry pits is also thought to eventually seep to Stout's Creek.

As shown in Table 1, each of these springs has been shown in the past to be transporting PCBs to Stout's Creek. This investigation will be conducted to gain more of an understanding on how this PCB transport is taking place.

3.0 Previous Investigations

3.1 On-scene Coordinator's Report

The report describes:

1. A small pond, possibly a spring, on the eastside of the fill,
2. An adjoining pond draining west toward Stout's Creek, and
3. A small pond along the west border of the site, situated between the fill and the railroad tracks, which flowed via two routes directly into Stout's Creek.

The report contains a site plan that shows that the first pond on the east side of the fill corresponds to the Mound Spring currently being sampled in the interim monitoring program. The third spring along the west corresponds to the Middle Spring, which is also being sampled as part of the interim monitoring program. The EPA sampled the water from the pond corresponding to the Middle Spring. The sample was analyzed at 7 ppb PCB Aroclor 1242.

3.2 BOB Supplemental Hydrogeologic Investigation

Between 1987 and 1989 Blasland and Bouck Engineers conducted the initial Hydrogeologic investigations. These investigations included:

• Installation of borings, which were eventually converted to monitoring wells
• Geophysical logging of the bore holes
• Permeability testing in the wells
• Monitoring well groundwater sampling for PCBs
• Groundwater elevation contour mapping to determine groundwater flow direction
• Construction of geologic cross-sections

The report, "Onsite Groundwater Monitoring Plan - Bennett's Dump, B&B, May 1989" (Reference 3), contains the results of these investigations. The report was mainly focused on groundwater conditions as revealed in the monitoring wells, although the report did note the presence of seeps. The overall groundwater flow direction as revealed by water levels in the wells was consistently west-northwest. Stout's Creek appears to be the discharge area for the groundwater. Based on water level measurements in well MW-61, MW-6D and MW-5 and the stream gaging station OS-2, there is an upward component of groundwater flow near the creek indicating groundwater discharge is into the creek.

This initial report was not clear on what features of the rock were supplying water to the monitoring wells. Fractures noted in cores did not seem to correlate with packer-test permeability. Few solution openings were noted in cores, but cores are not good places to note solution openings, as they often appear as core-loss or bit drops. The packer test results indicate that no major conduits (several inches or greater) were intersected by the well drilling.

3.2.1 i993 Video Logging

No major conduit connections to any of the existing monitoring wells were discovered during the video logging.

3.2.2 Aerial Photography Analysis

The "Phase 1 Progress Report, Winston Thomas Facility and Bennett's Dump", Blasland & Bouck, Engineers, P.C., January 1987, (Reference 4) discusses the results of this study. It also includes a 1984 air photo interpretation of the Bennett's Dump area, Bennett's Quarry, Indiana, Airphoto Interpretations, Liang, Ta, May 29, 1984 (Reference 5). Aerial photographs from 1939 through 1980 were analyzed.

The interpretation of the aerial photos shows the chronology of quarrying operations around and inside of the Bennett's Dump site. The 1939 air photos show the buried quarries with deep PCB contamination that were discovered during the 1999 remedial action (Section 3.3). These quarries were part of a complex of large quarry pus that extended toward the satellite area and Icebox Quarry. The aerial photos also show that there are a number of quarry pus upgradient of the Bennett's Dump she to the east and south that have since been filled in.

3.3 1999 Remedial Action

In 1999 the site was remediated according to the August 6, 1999, "Remedial Action Work Plan, Bennett's Dump, Monroe County, Indianan, CBS Corp., August 6, 1999 (Reference 6) which was approved by the CD parties.

The remediation was performed to satisfy the "Statement of Work (SOW) For the Remedial Action at Bennett's Dump, Monroe County, Indiana, August 26, 1999 (Reference 7) that required removal of soils and wastes containing concentrations greater than or equal to 50 ppm PCBs. The resulting average PCB concentration across the excavation was not to exceed 25 ppm. The excavation was backfilled with a minimum of 12 inches of clean cover, graded to drain, and revegetated.

Site remedial actions began in mid-August 1999 and were completed in early November 1999. The project involved:

• Shipping a total of 36,157 tons of TSCA material to the Environmental Quality Company's Wayne Disposal Landfill for disposal.
• Shipping a total of 1756 capacitors weighing 118.72 tons to Onyx Environmental in Port Arthur, Texas for incineration.
• The arithmetic average of all residual confirmation sample results is 11.3 ppm compared to the 25 ppm requirement of the SOW.
• The site was backfilled with approximately 25,000 cubic yards of clean clay, graded for drainage and seeded.

At three locations shown in Figure 2 the excavation revealed deep quarry pits filled with rubble and fill. The rubble consisted of large boulders and smaller, broken pieces of stone mixed with soil. At these locations, capacitor parts and PCB contaminated soils existed above the rubble. The capacitor parts and PCB soils were removed. Boulders and rubble were removed to the full reach of the excavator at 17 to 20 feet deep. Each of these excavations filled with Groundwater in contact with the rubble. The Groundwater had a light oil sheen in some locations. An oil sample was analyzed as being diesel fuel contaminated with PCBs. The water/oil mix was pumped and treated to allow the excavations to proceed. Residual oil and oil staining remains buried at the bottom of these excavations.

Samples were taken of dirt at the bottom of these excavations. Each of these areas produced sample results that exceeded the SOW allowable limit of 50 ppm. The locations and sample results of the subgrids that exceed the 50 ppm limit are:

The CD parties permitted Viacom to terminate excavation in each section after removing as much material as possible and collecting a final bottom grab sample. The average PCB concentration for all of grid H7 is 122 ppm, for grid F6 is 25.3 ppm and for grid G8 is 33 ppm. The subgrid locations and sample results are shown on Figure 3.

The satellite area presented a similar situation. A pit encompassing portions of grids S2 and S8 as shown in Figure 4 was discovered that was filled with capacitor carcasses, capacitor parts and large amounts of ash. The capacitors, and the soil and ash containing~the capacitor parts were removed to a depth of about 13 feet. Capacitors, capacitor parts and stained soils were chased and excavated out of the bottom and sidewalls in all directions. Sidewall samples were taken until the cleanup criteria was met in the north, east and south directions. The west sidewall of the satellite area was removed down to a depth of 7 feet below grade and extended 10 feet westward into a site access road. At this point all capacitors, capacitor parts, ash and soil had been removed from the excavation. The bottom and western sidewall consisted of only large boulders and rock debris all the way up to the gravel road bed. No appreciable soil or ash remained. The CD parties concurred that no further sampling or excavation was warranted in this area. Figure 4 shows that the final configuration of the burn pit excavation extended across grids S2, S8, S3 and S7. Figure 13 shows the relationship between the buried quarries in the main site area, the pit in the satellite area and the Icebox Quarry.

The remedial action is documented in "Final Report- Completion of Removal Action for Bennett's Dump, CBS Corp, February 7, 2000" (Reference 8).

3.4 Interim Groundwater Monitoring Program

The SOW (Reference 7) for the 1999 remedial action at Bennett's Dump called for an Interim Groundwater Monitoring Program. Prior to the start of excavation activities and every 60 days during remediation the following locations were to be sampled:

• South line of seeps
• North Spring at the culvert under the RR tracks
• MW-61
• MW-6D
• MW-3

Due to the dry conditions during the remediation in the summer and fall of 1999, the seeps and springs were not flowing. It was therefore agreed to add samples from Stout's Creek, upstream and downstream of the site. Also a sample was to be taken from the West Branch entrance to Stout's Creek as shown in Figure 1.

In February and March of 2000 the Middle Spring and the Mound Spring, as shown on Figure 1, were added to the interim monitoring program.

• Monitoring wells MW-61, MW-6D, and MOO-3
• Stouts Creek, upstream and downstream of the site
• The West Branch entrance to Stouts Creek
• All flowing springs on site

The locations of these sampling stations are shown on Figure 1. Table 1 shows the results of the Interim Groundwater Monitoring Program since before excavation started.

• Data from Groundwater monitoring wells installed around Bennett's Dump during EPA site assessments indicate that Groundwater levels are very near the ground surface in the vicinity of the dump, and that the horizontal flow direction is to the north and west. The data imply that at least a part of the interchange area is located hydraulically upgradient from Bennett's Dump. A complex of backfilled and idle quarry pits located between the existing highway, the interchange area and Bennett's Dump is probably hydrologically connected with the dump.
• EPA site assessment activities at Bennett's Dump in 1983 indicated that an active spring rise and a seep were present in the areas of fill, and that water from both sources flowed off the dump and into Stout's Creek. Therefore, alteration of surface drainage patterns or Groundwater flow patterns as a result of highway construction upgradient in the interchange area could potentially increase gro undwater discharge causing an increased release of PCBs from the Bennett's Dump Site.
• The complex of old quarry pits previously detained runoff to Stout's Creek from the east and may have reduced potential peak flows in the stream. Many of these pits were backfilled as a result of highway construction. If highway runoff can be routed through the remaining quarry pits (modified with outfalls between pits to prevent increases in head), the runoff contribution from the highway to Stout's Creek may be delayed such that it does not significantly increase peak flows of the stream at Bennett's Dump.

• Avoid routing additional runoff from the new interchange area into the old quarry complex to avoid providing additional Groundwater recharge to Bennett's Dump.
• Minimize runoff from the interchange area directly into Stout's Creek, and pass the runoff through the remaining unfilled quarry pits. Figure 5 shows the drainage from Highway SR 37 before construction. Figure 6 shows the routing of the new highway construction and the original proposed drainage. Figure 7 shows the revised drainage that Earth Tech proposed.

It appears that the Indiana Department of Transportation adopted the Earth Tech recommendations. Figures 8 and 9 show the interchange grading details planned by INDOT. Drainage from east of SR 37 is being diverted to south of the new SR 46, away from the Bennett's Dump site. Drainage appears to be directed into an open quarry pit just east of the box culvert being constructed under the new SR 46 for Stout's Creek. Figure 7 shows this revised proposed drainage configuration.

Drainage from the interchange that is directly upgradient of the site apparently is being diverted tangentially toward the north and to the southwest of the site as shown in Figure 7. This appears to still add this water to the groundwater recharge system within the old quarry complex that may be connected to the Bennett's Dump site groundwater system.

Construction in is progress on the interchange and the State Route 46 re-alignment. According to the INDOT site engineer, quarry pits along the highway right-of-way were to be backfilled with no dewatering. Surface water drainage was modified as the construction proceeded.

While Viacom agrees with the first recommendation made by Earth Tech, we disagree with the second. Viacom believes that surface water from the construction areas to the south and east of Bennett's Dump should be directed away from the site as directly as possible, not into the unfilled quarry pits.

Previous investigations, as discussed above, indicated that the unfilled quarries to the south and east of the site are upgradient of the site groundwater system. The connection between these quarry pits and the Bennett's Dump site is unknown at this time. Viacom therefore believes that allowing this water to accumulate in these quarries may provide additional groundwater recharge to Bennett's Dump. This would raise the groundwater levels under the site and increase the flow of the springs on site.

iacom believes that directing surface flow from the construction site directly to Stout's Creek and not into open quarry pits would have been preferred. This would have allowed the water to drain away from the site as fast as possible and not contribute to higher groundwater levels and increased spring flows at and around the site.

3.6 2001 IDEM Study

As indicated above, the SHIP investigations in the 1 980's determined that the groundwater flow direction around the Bennett's Dump site is to the north and west (Reference 3). Therefore the water filled quarries to the south and east of the site may serve to recharge the groundwater at the site.

An IDEM report "Hydraulic Considerations to Eliminate Contaminated Springs, Bennett's Quarry, Bloomington, Monroe County, Indiana, P.B.Schonhoff, IDEM, February 11, 2001" (Reference 10), discusses groundwater recharge to the site by quarry pits near the site. Phil Schonhoff of IDEM determined the elevations of the water in selected quarries to the east and southeast of the site. Figure 10 shows the location of the quarries and the site. The elevation of the Mound and Middle Spring emergences on site and Stout's Creek next to the site were also determined. Figure 11 shows a profile transect from one of the quarries to the springs and the creek. The profile shows that groundwater from the quarry has the potential to charge the springs on site.

The water samples that have been taken from the Mound and Middle springs have elevated PCB levels, as indicated in Table 1. Groundwater migrating from the quarries to the springs will pass through site grids where residual PCBs <25 ppm was left during the 1999 remedial action. The water migrating to the springs can also pass through the subgrids where PCB contamination up to 1100 ppm was left and residual PCB oil may exist, as discussed in section 3.3.

The 2001 IDEM memo recommends lowering the water levels in the upgradient quarries to stop the flow of the impacted springs. Viacom agrees that this may be possible. However, draining the upgradient quarries may cause the contaminated groundwater to then backflow to the quarries or into other buried quarries.

Viacom would like to gain a better understanding of the interaction between the water filled quarries and springs before lowering any quarry water levels.

4.0 Investigation Plan Objectives

The overall objective of this investigation is to gain additional information on the Bennett's Dump site hydrogeology, groundwater recharge and PCB transport from the site.

The individual objectives of this investigation are:

Further define the site hydrogeology and recharge area to understand the relationships between the groundwater elevations, water levels in the open quarry pits and spring flows at the site.
1. Obtain enough data to estimate the mass loading of PCBs to Stout's Creek under varying hydrologic conditions by determining the water flows and PCB levels of the various spring sources.
2. Determine the impact of the Route 46 highway construction on the local site groundwater flow. As part of the highway construction, water filled quarry pits were filled and surface water run off flows were modified. These changes will affect the Bennett's Dump site groundwater levels, spring flows, etc.

5.0 Investigation Plan Details

Groundwater and surface water conditions at and near Bennett's Dump will be investigated under normal and storm event conditions. Water flow rates will be monitored continuously in the perennial site springs during normal and storm flow conditions. Water flow rates will be monitored in Stout's Creek during storm events. PCB sampling will occur during both high and low flow conditions. Water levels will be monitored in quarry pits upgradient of the site, in the onsite monitoring wells and in a new piezometer installed in the H7 remediation grid area. As discussed in Section 3.3, PCB contamination was left deep in the bottom of the H7 excavation during the 1999 remediation, as shown in Figure 3.

During a storm event, the water level in the quarries will be correlated with rainfall, monitoring well levels, spring flow and PCB content, and creek flow and PCB content.

5.1 Investigation of Quarry Pits

The historical air photo interpretations reported in the B&B Phase 1 Progress Report (Reference 4) will be reviewed. The air photos will again be inspected for old quarry pits that have since been filled. The buried quarry pits that were excavated during the 1999 remedial action and found to contain PCB contamination will especially be of interest. The size and possible connection of these pits to the existing open pits will be studied. Filled quarry pits that are in the recharge area of the site and specifically in the recharge area of the subgrids with the deep PCB contamination will be identified.

An accurate inventory of quarry pits will be obtained. New aerial photos of the area south and east of the site will be taken. Quarry pits that are or have been filled during the highway construction will be identified.

A new topographic base map of the area including the new highway construction and the quarry pits in the recharge area to the south and east of the site will be generated. The number, size, and area of quarry pits will be quantified from aerial photos.

Staff gauges will be installed in selected quarry pits so that changes in water elevations in response to precipitation can be measured. Two quarry pits have initially been selected, as shown on Figure 5. The Icebox Quarry, which is the closest open quarry pit to the site, will have a staff gauge installed. Wedge Quarry, which is among a group of quarry pits to the southeast of the site that were discussed in the 2001 IDEM memo (section 3.6) will also be equipped with a staff gauge. It is assumed that the water level within a group of quarry pits in close proximity have a similar response. However, based on observation of the water levels, additional staff gauges may be mounted in other quarry pits within the group.

The open walls of the quarry pits will be examined so any salient geologic features, such as major joint sets or fracture traces, can be noted.

5.2 Stream and Spring Gauging and Monitoring Well Level

The stream gauging station in Stout's Creek that was used during the 1998 storm sampling event will be reactivated. The gauging station consists of a staff gauge that will allow the creek water level to be observed. A rating curve will be developed that will allow water level readings to be used to calculate creek water flow rate.

The gauging station will be reinstalled just upstream of the West Branch entrance. The rating curve will be updated so that flows up to 50,000 gpm can be determined. All downstream creek surface water PCB samples will be taken at the gauging station under both normal flow conditions and storm sampling events. A transducer will be installed at the gauging station to continuously log creek flow readings at all times.

Nine inch V-notch weirs will be installed at the Middle Spring and Mound Spring to measure up to 400 gpm flow rates. In-Situ Inc. miniTroll datalogging pressure transducers will be installed to log water levels at each weir. The weirs will be installed within about 10 feet of the spring emergences, in drainage ditches that collect all the spring flow and direct it to the weirs. The drainage ditches run due west from the spring emergences to Stout's Creek. Figures 12 and 12a show photographs of the weir installations. Modifications will be made to collect most of the water emerging from each spring and to direct it to the respective weir. There may be some additional spring flows during extreme wet conditions that will bypass these weirs, but the installations should give a good indication of the spring flows

As indicated above, water level will be measured in all the existing monitoring wells on site (MW-1, MW-3, MW5, MW-61, and MW-6D) under normal conditions and during a storm event. As stated in Section 5.0, a new piezometer has been installed in the H7 remediation grid area which will be used to monitor ground water level in this buried quarry area.

Groundwater levels in the monitoring wells and the piezometer at the site will be compared to spring flow, stream flow and quarry pit levels. The purpose of monitoring the wells is to determine if any of the existing wells appear to be connected to the springs. If the water level changes in any of the monitoring wells correlate with spring flows, one well will be picked for future monitoring. The well that shows the best response will be selected. Datalogging instrumentation may be installed in the selected monitoring well.

5.2.1 Topographic and Potentiometric Maps

One new topographic map will be produced of the present Bennett's Dump site surface including the elevation of spring emergences, well heads, Stout's Creek and other onsite surface features. The topographic map will include the state planar coordinate grid referenced to the coordinate grid utilized during the removal action, a monitoring well and stage datum point schedule, the coordinates, elevations and locations of survey control points, and the coordinates, elevations and locations of quarry monitoring points.

Water levels in the open quarries and existing monitoring wells will be compared to the elevation of the spring emergences and the water flow rates from the springs. A potentiometric map of the subsurface Groundwater flow will be produced based on observations of Groundwater levels in the quarries and wells/piezometers, and the spring flows.

5.3 Monitor Effects of Highway Construction

The effects on the Benrett's Dump hydrology caused by the highway construction will be monitored. Quarry water levels, spring flows and Groundwater levels at the site will be monitored. Surface water runoff will be correlated to topographic changes resulting from the highway construction. As indicated above, aerial photos will be taken to document the construction.

5.4 PCB Sampling and Data Analysis

As part of the Long-term Groundwater Monitoring Plan (Reference 11 ) to be perfommed by Viacom, water samples for PCB analysis will be collected quarterly from each flowing spring on site and from Stout's Creek immediately upstream and downstream of the site. For this investigation additional samples will be taken monthly for a year and analyzed for PCBs.

Also, the long-term monitoring plan calls for an annual sampling event of Stout's Creek during a major spring storm. The storm will total at least one inch of rainfall. The flow in the creek will be measured continuously during the storm event while upstream and downstream PCB samples will be taken. PCB sampling and flow data logging will also be performed at the Middle Spring and Mound Spring during the storm event. Any other onsite springs flowing during the storm event will also be sampled. Estimates of these flows will be made when the water samples are taken.

During stomm conditions, samples may be taken with an ISCO auto sampler. Each sample will be approximately 500 ml and taken into a glass container in the base of the sampler on an hourly basis until 10 hours after the peak flow. Then the frequency may be decreased if detemmined by the sampling crew to be appropriate. When auto samplers are used to collect stomm samples, the sampler will be iced. The maximum amount of time that a sample will be left in the sampler before it is removed, sealed and refrigerated will be limited to 12 to 16 hours.

As part of this investigation plan, PCB levels will be correlated with spring flows and Groundwater elevations. Mass loading of PCB's to Stout's Creek from all the sampled spring sources will be calculated. PCB mass loading in Stout's Creek will be estimated based on PCB content downstream of the site and the flow rate of Stout's Creek. This value will be compared to the sum of the mass loading of all the known, measured sources.

It should be noted that attempting to close a PCB mass and flow balance with data from three different locations may not be possible because of the inherent inaccuracies in the data. However, the mass and flow balance should be able to show if there are other major sources, which are not being included in the measurements and calculations.

5.5 MW-5 Monitoring

As indicated in the Bennett's Dump Long-term Groundwater Monitoring Plan (Reference 11) the use of MW-5 was discontinued in March 1988 due to the presence of free PCB product within the well. Viacom examined MW-5 in September 2001 and discovered that an undetermined amount of free phase product mixed with sediment still remained at the bottom of the well. For the duration of the September examination, the amount of free phase product in MW-5 did not appear to increase.

As specified in the long-term Groundwater monitoring plan, Viacom will purge MW-5 of PCBs and then observe the well during the monitoring period to determine if free product returns.

A decision will then be made by the parties on any further actions to be taken at this monitoring well.

6.0 Reporting

Interim reports providing raw data will be sent out on a quarterly basis. Viacom will work with the parties to develop a process to provide stage and flow data, water level data and water quality data in an electronic format. Other interim topical reports will be sent to the parties as they are completed.

A final report with an analysis of all data and investigations will be prepared several months after sufficient data is collected to support conclusions. It is anticipated that the report will be issued by mid-2003.

Based on the data evaluation and conclusions, Viacom may recommend additional interim or follow-on investigation activities. Therefore, a "phased" investigation of the Groundwater conditions for Bennett's Dump may be performed by Viacom.

References

1. On Scene Coordinator's Report, USEPA, June 1983.
2. Supplemental Hydrogeologic Investigation Plan (SHIP), Winston Thomas and Bennett's Dump, Blasland and Bouck Engineers, P.C., August 1986.
3. Onsite Groundwater Monitoring Plan - Bennett's Dump, B&B, May 1989. (Reference 5-17).
4. Phase 1 Progress Report, Winston Thomas Facility & Bennett's Dump, Blasland & Bouck, Engineers, P.C., January 1987 (Reference 5-10).
5. Bennett's Quarry, Indiana, Airphoto Interpretation, Liang, Ta, May 29,1984 (Reference 5-10c).
6. Remedial Action Work Plan, Bennett's Dump, Monroe County, Indiana, CBS Corp., April 23, 1999. ,
7. Statement of Work (SOW) For the Remedial Action at Bennett's Dump, Monroe County, Indiana, August 26, 1999.
8. Final Report - Completion of Removal Action for Bennett's Dump, CBS Corp, February 7, 2000.
9. Highway Runoff from the Proposed State Road 46/State Road 37 Interchange Area, Bloomington, Indiana (INDOT Project NH-062-4(008)), Earth Tech, May 16, 1997.
10. Hydraulic Considerations to Eliminate Contaminated Springs, Bennett's Quarry, Bloomington, Monroe County, Indiana, P.B. Schonhoff, IDEM, February 11, 2001.
11. Viacom Inc., "Long-term Groundwater Monitoring Plan, Bennett's Dump", March 2002.